Prostate cancer (PCa) is the No. 2 killer among male cancer patients. The ultimate test is based on transrectal ultrasound guided needle biopsy and histological examination of fixed prostate tissues. This conventional diagnostic procedure is invasive, missing 30% cases of cancer due to small sampling volume. Moreover, it leads to an overtreatment of patients due to low specificity in diagnosing aggressive cancers. To address this pressing need, Vibronix, Inc. and its research partners at Purdue University and Indiana University School of Medicine propose to develop a spectroscopic vibrational photoacoustic tomography (VPAT) system for PCa diagnosis using cholesteryl ester accumulation as biomarker. As an Indiana-based small business, Vibronix, Inc.'s long-term goal is to bring the VPAT technology from bench top to bedside. The central hypothesis of this STTR project is that the VPAT system can measure the size of the tumor in intact prostate tissue. Vibronix, Inc. along with its research partners have formed an interdisciplinary team to test this hypothesis. Dr. Ji-Xin Cheng (PI) the first to demonstrate CE accumulation as a marker for PCa. His lab also demonstrated the first VPAT system 6. Dr. Liang Cheng (MD) is a professor in Department of Pathology in Indiana University School of Medicine (IUSM) and will perform pathological grading of the prostatectomy samples. Dr. Timothy Masterson (MD) is an Assistant Professor of Urology and specializes in the treatment of adult genitourinary cancers. The proposed hypothesis can be tested through the following specific aims: (1) Demonstrate a miniaturized VPAT system with an imaging depth of 3 cm. (2) Demonstrate spectroscopic VPAT imaging of intact prostate gland using CE as a biomarker to differentiate normal and cancerous prostate tissues, and the measurement of the tissue volume. Deliverable: Upon successful design and evaluation of the transrectal spectroscopic VPAT system, we will have generated a new imaging technology for measure the prostate tumor volume in an intact prostate gland using CE as a biomarker. This advance will pave the foundation for a phase II study in which in vivo VPAT imaging will be performed and CE accumulation will be correlated with aggressiveness of PCa. Eventually, our VPAT technology, in a minimally invasive manner, would assist a physician to diagnose PCa objectively and to decide whether prostatectomy surgery is needed.